1. Field of the Invention
The invention relates generally to the field of powered tools and more specifically to the field of machine wrenches for making or breaking threaded pipe joints.
2. Related Art
Drilling long holes in earth, whether in rock or unconsolidated material and whether for water, oil, exploration, or other purpose, invariably requires the connection of lengths of round or nearly round drill rod or drill pipe. Such drill rod or pipe is normally connected by threading the male threads at the bottom of one pipe into the female threads at the top of the other pipe, every drill pipe having male and female threads at opposing ends. Drill holes are advanced by "making" increasingly longer drill strings by spinning together lengths of such pipe. Conversely, the drill strings are subsequently removed and the drill pipe is recovered by reversing the process, thus "breaking" the pipe joints by spinning them apart. The present invention provides significantly improved means to accomplish the necessary spinning of drill pipes for making and breaking connections. The preferred embodiment described herein is directed toward water well drilling pipes, including casing, of generally 4" to 8" outside diameter, although it is reasonably adaptable to other round drill pipes and rods of other diameters.
A variety of related art has addressed drill pipe spinning by way of various configurations of motors, drive trains, and means for moving and retaining pipe sections. Brooks in U.S. Pat. No. 4,381,685 (issued May 3, 1983) discloses a tool for rotating a length of pipe to make or break a pipe joint comprising a single motor driving a single drum with serrated surface which imparts spinning motion to the subject pipe section when it is pressed against the drive drum by way of a C-shaped clamp and manpower. Hudson in U.S. Pat. No. 4,221,269 (issued Sep. 9, 1980) discloses a "pipe spinner" comprising three rotary hydraulic motors mounted coaxially within three urethane coated drive rollers which impart spin when pipe is pressed within the three rollers by way of one or two hydraulic rams. Gibson in U.S. Pat. No. 4,178,817 (issued Dec. 18, 1979) discloses a powered wrench comprising a single motor driving, by way of worm gear, a single "driving roll" with flattened teeth and embracing the drill pipe by way of idlers within an arcuate retainer closed by chain and hooks. Goodman in U.S. Pat. No. 3,774,481 (issued Nov. 27, 1973) discloses a device much like Gibson with a single motor, worm gear drive, and strap and idler means for enclosure but with various drive means including double drive rollers in one embodiment and an "endless toothed belt" in another. Duke in U.S. Pat. No. 3,521,509 (issued Jul. 21, 1970) discloses a power wrench comprising a single motor with a single ring gear driving two frictional contact wheels and an "idle wheel housing" with air ram telescope to close the pipe on the drive wheels. Bartos in U.S. Pat. No. 3,392,609 (issued Jul. 16, 1968) discloses a "well pipe spinning unit" comprising a single rotary pneumatic motor with gear train driving four pairs of drive rollers which engage a pipe length upon closure by a single piston and cylinder mechanism. Guier in U.S. Pat. No. 3,308,691 (issued Mar. 14, 1967) discloses an unusual resilient shock absorbent collar configured around the pipe and within an endless chain which is driven by a single motor. Other power wrenches are disclosed in other patents. None, however, describe the particular configuration of components or realize the inherent advantages of the present invention.